Giga Trees

Around the year 2150 the company Geotech released their newest invention, the giga tree. These trees were genetically engineered super trees used to clean out the ever increasing carbon in the air. They grew to be as tall as one of the 500 m in the span of 4 years. One year after the first test speed was planted they realized they forgot to remove its seed genome, but it was to late. The giga trees had already uncontrollably spread across the US, locking out North America from the ever growing city planet. The giga trees have created the last known natural green area on earth and have created their own unique ecosystem. As far as we know no seeds have made it to the Eurasian city-continent. Although, they have done their job as carbon levels have returned to a stable state since then.